Fetal Nasal Bone

In 1866, Langdon Down noted several features in individuals with trisomy 21 which included a small nose, flat facies, and poor skin elasticity. In 1997 Keeling, Hansen, and Kjaer reported an absent nasal bone in fetuses with trisomy 21. In November, 2001, Cicero et al reported in the Lancet the association between trisomy 21 and absence of the nasal bone in fetuses with trisomy 21 examined between 11 and 14 weeks of gestation. They found that the nasal bone was absent in 72.8% of fetuses with trisomy 21, 55% with trisomy 18, and 25% with Turner's syndrome. It was present in fetuses with trisomy 13, XXX, Klinefelter's syndrome, or triploidy. Using this marker, coupled with nuchal translucency and maternal age, a risk of 1 in 300 or higher will identify 92% of fetuses with trisomy 21 with a false-positive rate of 3% . However, before one can use the presence or absence of the nasal bone as a marker for trisomy 21, the ability to identify this structure accurately is necessary. This section will discuss normal anatomy, abnormal anatomy, and diagnostic errors that can occur when attempting to identify the presence or absence of the nasal bone during the first-trimester examination .

Identification of the Nasal Bone

The nasal bone actually consists of two bones, one on the right and one on the left. Traditional imaging using real-time B-mode ultrasound, can only identify one bone at a time. The image below this text illustrates this.

 This represents three imaging modalities that identify early fetal development. The fetus on the left is an actual photo at 12 weeks. The fetus in the middle is from an MRI study and the fetus on the right is an ultrasound. The nasal bone is identified in each image.

The visualization of the nasal bone was described by Cicero et. al. as follows:

"For examination of the fetal nose, a mid-sagittal view of the fetus was obtained, with the beam of the ultrasound transducer being parallel to the nasal bone. In this position, the skin of the nose produces an echogenic line, which can be misinterpreted as the nasal bone. To avoid this mistake, the ultrasound transducer was gently tilted from side to side to ensure that the nasal bone was seen separate from the nasal skin."

The Use of 2D Ultrasound to Evaluate the Nasal Bone

Evaluation of the nasal bone was first described using 2D ultrasound in which the nasal bone was identified in the sagittal plane, which only images one nasal bone at a time.  Since the nasal bone consists of two bones, Dr. DeVore prefers to identify both bones by directing the ultrasound beam in a transverse plane.  Using this approach both nasal bones can simultaneously be identified.  This is a similar approach described below using 3D ultrasound.

The Use of 3D Ultrasound to Evaluate the Nasal Bone

The most important part of obtaining the image of the nasal bone is proper alignment of the beam to image this structure. To assist in the examination of the nasal bone, 3D-multiplaner imaging is useful because it allows the examiner to align the sagittal image of the head and accurately identify the nasal bone. The following images demonstrates the proper sagittal image for identification of the nasal bone.

 This image demonstrates the plane of the falx, which is a midline structure of the brain. Lateral to the falx is the choroid plexus (CP) located on the right and left sides of the midline, which is present in the transverse and coronal images. The correct plane of the sagittal image of the head contains the falx, but not the choroid plexus. The tip of the nose is hyperechoic, but is not the location of the nasal bone.


 This image illustrates the planes of the coronal and transverse images using the sagittal image as the reference plane. The blue line in the sagittal plane corresponds to the transverse plane and the yellow line to the coronal plane. The nasal bone is identified by the purple arrows. Using this approach, the nasal bone can be accurately identified and confirmed to be present in all three planes


 This is a 3D holographic rendering of the facial bones. The green line indicates the plane of the rendering, which is located in front of the nasal bone. Examine the holographic image and identify the nasal bone.


 This compares two fetuses, in which the sagittal images were obtained in the midline in which the falx is present and not the choroid plexus. The nasal bone is present in the normal fetus and absent in the abnormal fetus with the increased nuchal translucency.

Medical Literature


Chen M, Lee CP, Tang R, Chan B, Ou CQ, Tang MH.
First-trimester examination of fetal nasal bone in the Chinese population.
Prenat Diagn. 2006 May 25; [Epub ahead of print]

Related Articles, Links


Kozlowski P, Knippel AJ, Froehlich S, Stressig R.
Ultraschall Med. 2006 Feb 22; [Epub ahead of print] German.

Related Articles, Links


Prefumo F, Sairam S, Bhide A, Thilaganathan B.
First-trimester nuchal translucency, nasal bones, and trisomy 21 in selected and unselected populations.
Am J Obstet Gynecol. 2006 Mar;194(3):828-33.

Related Articles, Links


Ramos-Corpas D, Santiago JC, Montoya F.
Ultrasonographic evaluation of fetal nasal bone in a low-risk population at 11-13 + 6 gestational weeks
Prenat Diagn. 2006 Feb;26(2):112-7.

Related Articles, Links


Cicero S, Spencer K, Avgidou K, Faiola S, Nicolaides KH.
Maternal serum biochemistry at 11-13(+6) weeks in relation to the presence or absence of the fetal nasal bone on ultrasonography in chromosomally abnormal fetuses: an updated analysis of integrated ultrasound and biochemical screening.
Prenat Diagn. 2005 Nov;25(11):977-83.

Related Articles, Links


Maymon R, Neeman O, Shulman A, Rosen H, Herman A.
Current concepts of Down syndrome screening tests in assisted reproduction twin pregnancies: another double trouble.
Prenat Diagn. 2005 Sep;25(9):746-50. Review.

Related Articles, Links


Monni G, Zoppi MA, Ibba RM, Floris M, Manca F, Axiana C.
Nuchal translucency and nasal bone for trisomy 21 screening: single center experience.
Croat Med J. 2005 Oct;46(5):786-91.

Related Articles, Links


Nicolaides KH, Wegrzyn P.
[Sonographic features of chromosomal defects at 11(+0) to 13(+6) weeks of gestation]
Ginekol Pol. 2005 Jun;76(6):423-30. Review. Polish.

Related Articles, Links


Wenstrom KD.
First-trimester Down syndrome screening: component analytes and timing for optimal performance.
Semin Perinatol. 2005 Aug;29(4):195-202. Review.

Related Articles, Links


Nicolaides KH.
First-trimester screening for chromosomal abnormalities.
Semin Perinatol. 2005 Aug;29(4):190-4. Review.

Related Articles, Links


Prefumo F, Sethna F, Sairam S, Bhide A, Thilaganathan B.
First-trimester ductus venosus, nasal bones, and Down syndrome in a high-risk population.
Obstet Gynecol. 2005 Jun;105(6):1348-54.

Related Articles, Links


Orlandi F, Rossi C, Orlandi E, Jakil MC, Hallahan TW, Macri VJ, Krantz DA.
First-trimester screening for trisomy-21 using a simplified method to assess the presence or absence of the fetal nasal bone.
Am J Obstet Gynecol. 2005 Apr;192(4):1107-11.

Related Articles, Links


Nicolaides KH, Wegrzyn P.
[First trimester diagnosis of chromosomal defects]
Ginekol Pol. 2005 Jan;76(1):1-8. Review. Polish.

Related Articles, Links


Krampl E.
[Screening of chromosome anomalies during the first trimester]
Gynakol Geburtshilfliche Rundsch. 2005 Apr;45(2):86-92. German.

Related Articles, Links


Filkins K, Koos BJ.
Ultrasound and fetal diagnosis.
Curr Opin Obstet Gynecol. 2005 Apr;17(2):185-95. Review.

Related Articles, Links


Lapaire O, Sartorius G, Holzgreve W, Tercanli S.
[Sonographic first trimester screening in Switzerland]
Schweiz Rundsch Med Prax. 2005 Feb 9;94(6):199-204. German.

Related Articles, Links


Eiben B, Glaubitz R.
First-trimester screening: an overview.
J Histochem Cytochem. 2005 Mar;53(3):281-3. Review.

Related Articles, Links


Nicolaides KH, Spencer K, Avgidou K, Faiola S, Falcon O.
Multicenter study of first-trimester screening for trisomy 21 in 75 821 pregnancies: results and estimation of the potential impact of individual risk-orientated two-stage first-trimester screening.
Ultrasound Obstet Gynecol. 2005 Mar;25(3):221-6.

Related Articles, Links


Goncalves LF, Espinoza J, Lee W, Romero R.
Should the frontal bone be visualized in midline sagittal views of the facial profile to assess the fetal nasal bones during the first trimester?
Ultrasound Obstet Gynecol. 2005 Jan;25(1):90-2. No abstract available.

Related Articles, Links


Malone FD, Ball RH, Nyberg DA, Comstock CH, Saade G, Berkowitz RL, Dugoff L, Craigo SD, Carr SR, Wolfe HM, Tripp T, D'Alton ME; FASTER Research Consortium.
First-trimester nasal bone evaluation for aneuploidy in the general population.
Obstet Gynecol. 2004 Dec;104(6):1222-8

Related Articles, Links


Hui PW, Lee CP, Leung WC, Tang MH.
Is there an optimal gestation for ultrasound examination of fetal nasal bone in the first trimester?
Prenat Diagn. 2004 Nov;24(11):926-8. No abstract available.

Related Articles, Links


Nicolaides KH.
Nuchal translucency and other first-trimester sonographic markers of chromosomal abnormalities.
Am J Obstet Gynecol. 2004 Jul;191(1):45-67. Review.

Related Articles, Links


Kelekci S, Yazicioglu HF, Oguz S, Inan I, Yilmaz B, Sonmez S.
Nasal bone measurement during the 1st trimester: is it useful?
Gynecol Obstet Invest. 2004;58(2):91-5. Epub 2004 May 12.

Related Articles, Links


Brigatti KW, Malone FD.
First-trimester screening for aneuploidy.
Obstet Gynecol Clin North Am. 2004 Mar;31(1):v, 1-20. Review.

Related Articles, Links


Bahado-Singh RO, Cheng CS.
First trimester prenatal diagnosis.
Curr Opin Obstet Gynecol. 2004 Apr;16(2):177-81. Review.

Related Articles, Links


Fong KW, Toi A, Salem S, Hornberger LK, Chitayat D, Keating SJ, McAuliffe F, Johnson JA.
Detection of fetal structural abnormalities with US during early pregnancy.
Radiographics. 2004 Jan-Feb;24(1):157-74.

Related Articles, Links


Prefumo F, Sairam S, Bhide A, Penna L, Hollis B, Thilaganathan B.
Maternal ethnic origin and fetal nasal bones at 11-14 weeks of gestation.
BJOG. 2004 Feb;111(2):109-12.

Related Articles, Links


Malone FD, D'Alton ME; Society for Maternal-Fetal Medicine.
First-trimester sonographic screening for Down syndrome.
Obstet Gynecol. 2003 Nov;102(5 Pt 1):1066-79. Review.

Related Articles, Links


Viora E, Masturzo B, Errante G, Sciarrone A, Bastonero S, Campogrande M.
Ultrasound evaluation of fetal nasal bone at 11 to 14 weeks in a consecutive series of 1906 fetuses.
Prenat Diagn. 2003 Oct;23(10):784-7.

Related Articles, Links


Wong SF, Choi H, Ho LC.
Nasal bone hypoplasia: is it a common finding amongst chromosomally normal fetuses of southern Chinese women?
Gynecol Obstet Invest. 2003;56(2):99-101. Epub 2003 Aug 25.

Related Articles, Links


Wong SF, Ng WF, Ho LC.
Histopathological findings of the nose of Down syndrome abortuses.
Prenat Diagn. 2003 Jul;23(7):561-3.

Related Articles, Links


Orlandi F, Bilardo CM, Campogrande M, Krantz D, Hallahan T, Rossi C, Viora E.
Measurement of nasal bone length at 11-14 weeks of pregnancy and its potential role in Down syndrome risk assessment.
Ultrasound Obstet Gynecol. 2003 Jul;22(1):36-9.

Related Articles, Links


Cicero S, Longo D, Rembouskos G, Sacchini C, Nicolaides KH.
Absent nasal bone at 11-14 weeks of gestation and chromosomal defects.
Ultrasound Obstet Gynecol. 2003 Jul;22(1):31-5.

Related Articles, Links


Larose C, Massoc P, Hillion Y, Bernard JP, Ville Y.
Comparison of fetal nasal bone assessment by ultrasound at 11-14 weeks and by postmortem X-ray in trisomy 21: a prospective observational study.
Ultrasound Obstet Gynecol. 2003 Jul;22(1):27-30.

Related Articles, Links


Minderer S, Gloning KP, Henrich W, Stoger H.
The nasal bone in fetuses with trisomy 21: sonographic versus pathomorphological findings.
Ultrasound Obstet Gynecol. 2003 Jul;22(1):16-21.

Related Articles, Links


Zoppi MA, Ibba RM, Axiana C, Floris M, Manca F, Monni G.
Absence of fetal nasal bone and aneuploidies at first-trimester nuchal translucency screening in unselected pregnancies.
Prenat Diagn. 2003 Jun;23(6):496-500.

Related Articles, Links


Ferriman E, Cuckle H.
Case report: clinical utility of ultrasound nasal bone determination in the prenatal diagnosis of Down syndrome.
Prenat Diagn. 2003 May;23(5):433-4. No abstract available.

Related Articles, Links


Nicolaides KH.
Screening for chromosomal defects.
Ultrasound Obstet Gynecol. 2003 Apr;21(4):313-21. No abstract available.

Related Articles, Links


Cicero S, Bindra R, Rembouskos G, Spencer K, Nicolaides KH.
Integrated ultrasound and biochemical screening for trisomy 21 using fetal nuchal translucency, absent fetal nasal bone, free beta-hCG and PAPP-A at 11 to 14 weeks.
Prenat Diagn. 2003 Apr;23(4):306-10.

Related Articles, Links


Broussin B, Sarramon MF.
[Nuchal translucency: technical measurement and value]
J Radiol. 2002 Dec;83(12 Pt 2):1891-8. Review. French.

Related Articles, Links


Snijders R, Smith E.
The role of fetal nuchal translucency in prenatal screening.
Curr Opin Obstet Gynecol. 2002 Dec;14(6):577-85. Review.

Related Articles, Links


Otano L, Aiello H, Igarzabal L, Matayoshi T, Gadow EC.
Association between first trimester absence of fetal nasal bone on ultrasound and Down syndrome.
Prenat Diagn. 2002 Oct;22(10):930-2.

Related Articles, Links


Monni G, Zoppi MA, Ibba RM.
Absence of nasal bone and detection of trisomy 21.
Lancet. 2002 Apr 13;359(9314):1343. No abstract available.

Related Articles, Links


Cicero S, Curcio P, Papageorghiou A, Sonek J, Nicolaides K.
Absence of nasal bone in fetuses with trisomy 21 at 11-14 weeks of gestation: an observational study.
Lancet. 2001 Nov 17;358(9294):1665-7.

Related Articles, Links